In recent years, multimedia communications over wired and/or wireless packet communications networks such as the Internet have gained increased popularity. Such multimedia communications can be performed within the context of video conferencing systems, in which multipoint control unit(s) (MCU(s)) are typically employed to facilitate collaboration among groups of conference participant devices by performing various functions such as mixing, synchronizing, encoding, decoding, and/or transcoding video bitstreams and/or audio bitstreams generated by the respective conference participant devices.
In order to maintain an acceptable multimedia quality of experience (QoE) for a group of conference participant devices in such video conferencing systems, separate video encoders of an MCU can be assigned for sole use by the respective conference participant devices. Moreover, in order to maintain a high level of performance in such video conferencing systems, some or all of the conference participant devices can share, at least at some times, the same video encoder of the MCU. However, in conventional video conferencing systems, it can be difficult to balance the tradeoff between the benefits of maintaining an acceptable multimedia QoE for the respective conference participant devices, and maintaining a high level of performance for the overall video conferencing systems.
In addition, in such video conferencing systems, successful transmissions of multimedia data between an MCU and a group of conference participant devices over a packet communications network generally require sufficient bandwidth and low latency for minimal packet loss. Such transmissions of multimedia data between the MCU and the respective conference participant devices are typically based upon the real-time transport protocol (RTP), while delivery of such multimedia data to the respective conference participant devices is typically monitored by the MCU using the real-time transport control protocol (RTCP). For example, a respective conference participant device that receives multimedia data in the form of RTP packets from the MCU can provide packet error feedback information to the MCU in one or more RTCP feedback packets.
Maintaining successful multimedia communications in such video conferencing systems can be problematic, however, particularly when transmissions of multimedia data are performed over packet communications networks such as the Internet. For example, while engaging in video conferencing over the Internet, a group of conference participant devices may be subjected to different levels of network congestion, which can result in reduced bandwidth, increased latency, and ultimately increased packet losses, potentially degrading the multimedia QoE for one, some, or all of the respective conference participant devices in the group.
The situation can be even more problematic when some of the conference participant devices in a group share the same video encoder of an MCU. For example, if a respective one of the conference participant devices in the group has a video encoder assigned to it for its sole use, and, at some point, the respective conference participant device experiences increased packet losses, then the respective conference participant device can provide packet error feedback information to the MCU. Further, having received the packet error feedback information from the respective conference participant device, the MCU can react to the packet error feedback information by providing one or more control parameters to the video encoder in an effort to improve the multimedia QoE for that respective conference participant device.
However, if the respective conference participant device that experiences increased packet losses were instead required to share a video encoder with another conference participant device(s) in the group, then the MCU's reaction to the packet error feedback information, while possibly improving the multimedia QoE for the respective conference participant device currently experiencing packet losses, may inadvertently degrade the multimedia QoE for the other conference participant device(s) in the group.